1. Field of the Invention
This invention, generally, relates to multi-system data processing environments; and more specifically, the invention relates to common queues in such processing environments.
2. Background Art
Over the past several years, computer manufacturers have begun to provide processing architectures based on a multi-system shared data approach. Through these architectures, multiple large-scale computer systems, each of which is often referred to as a computer processing complex (CPC) or a central electronic complex (CEC), are interconnected, through, for example, a coupling facility or other interprocessor communication mechanism, to permit each such system to gain read-write access to data residing on one or more shared input/output devices. The resulting interconnected computer system is commonly referred to as a sysplex.
In these multi-processor environments, the coupling facility, among other functions, may provide a common, or shared, task queue for the connected, distributed computer complexes. With a common queue, tasks or requests can be placed on the queue by any of the connected computer complexes, and any of the interconnected computer systems can retrieve a request from the queue for processing. In this way, the total workload of the sysplex can be distributed among all the individual computer systems. Also, a computer system of the sysplex can receive a request from a client, even though that particular system cannot itself process the request. In this case, the work request is placed on the queue for processing by one of the other systems that can process the request.
One difficulty with a common queue in the coupling facility is that it applies to the whole sysplex. In an environment having multiple, dispersed, parallel systems, not all of the dispersed systems may be able to process all requests. This may be due to the fact that some of the systems do not have the physical devices or accessories needed to perform certain tasks. For example, the tape drive required for mounting tapes may not be physically co-resident with the tape cartridge media itself.
Also, in other situations, users of the systems may need to dedicate subsets of the distributed processors for specific purposes. For instance, a user may need or want to designate one subset of the parallel systems for production purposes, and to designate a second subset for test purposes. These users may want to have a different processing queue, within the common coupling facility, for each subset of the computer complexes.